authentication failed

Hi everyone!
when I try to log in into my self-serve portal https://central.sophos.com/manage/self-service which I was able to do before, it says

Authentication failed. Please check your credentials and try again.

I am sure the password is right since I have a Sophos central account on a different email and use the same password without problems.

then I click on forgot password, I get the code on my email enter it verify it - get a prompt to enter a new password, create a password that was not used before, and I still get

Authentication failed. Please check your credentials and try again.
  • We've verified your email address. You can now create a new password.
    I've used a browser I never use in incognito and every other option, cache, passwords clear etc.
this is something that's started happening with more users in my organisation